Film for semiconductor back surface and its use

ABSTRACT

It is an object of the present invention to provide a film for semiconductor back surface having reworkability, and an application of the film. A film for semiconductor back surface has: an adhering strength at 70° C. of 7 N/10 mm or less to a wafer before the film is thermally cured; and a rupture elongation at 25° C. of 700% or less. The film for semiconductor back surface preferably has a degree of swelling due to ethanol of 1% by weight or more. The film for semiconductor back surface preferably contains an acrylic resin.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a film for a semiconductor back surfaceand its use.

Description of the Related Art

In recent years, thinning and downsizing of a semiconductor device andits packaging have been further required. Because of that, a flip-chipsemiconductor device, in which a semiconductor element such as asemiconductor chip is mounted on a substrate by flip-chip bonding(flip-chip bonded), has been widely used as a semiconductor device andits packaging. In the flip-chip bonding, a circuit surface of asemiconductor chip is fixed to an electrode forming surface of thesubstrate in a way that the circuit surface is facing to the electrodeforming surface. In such semiconductor device, etc., the back surface ofthe semiconductor chip may be protected by a protective film to preventthe semiconductor chip from damage, etc (for example, refer to PatentDocuments 1 to 3).

PRIOR ART DOCUMENT Patent Document

Patent Document 1: JP-A-2008-166451

Patent Document 2: JP-A-2008-006386

Patent Document 3: JP-A-2007-261035

SUMMARY OF THE INVENTION

At the production of the semiconductor device, a film for semiconductorback surface is typically used as follows. First, a film forsemiconductor back surface is bonded onto the back surface of asemiconductor wafer (in many cases, a non-circuit-formed surface). Next,the semiconductor wafer is diced together with the film forsemiconductor back surface to forma semiconductor element. Subsequently,the semiconductor element with the film for semiconductor back surfaceis picked up, and the semiconductor element is then flip chip-connectedonto an adherend such as a substrate. The film for semiconductor backsurface is thermally cured as necessary. Consequently, a flip chip typesemiconductor device is obtained.

Herein, when the film for semiconductor back surface is bonded onto thesemiconductor wafer, air bubbles may enter, or misalignment in bondingposition may occur. The semiconductor device cannot be subjected to thenext step in such a state, and this requires a procedure (rework) ofpeeling the film for semiconductor back surface from the semiconductorwafer and bonding a different (another) film for semiconductor backsurface onto the semiconductor wafer.

Thus, reworkability which makes it possible to peel the film forsemiconductor back surface from the semiconductor wafer and reuse thesemiconductor wafer is required for the film for semiconductor backsurface. However, the film for semiconductor back surface generally hasa high adhering strength from the viewpoint of the continuous protectionof the back surface of a semiconductor chip, and the reworkability ofthe film for semiconductor back surface has not yet been studied.

The present invention has been made in view of the foregoing problems,and it is an object of the present invention to provide a film forsemiconductor back surface having reworkability, and an application ofthe film.

The present inventors earnestly studied for the purpose of solving theexisting problems, and found that, by employing the followingconstitution, a film for semiconductor back surface having goodreworkability can be provided. As a result, they completed the presentinvention.

That is, the present invention relates to a film for semiconductor backsurface having: an adhering strength at 70° C. of 7 N/10 mm or less to awafer before the film is thermally cured; and a rupture elongation at25° C. of 700% or less.

Since the film for semiconductor back surface has a low adheringstrength at 70° C. of 7 N/10 mm or less to a wafer before the film isthermally cured, the film for semiconductor back surface is easilypeeled from a semiconductor wafer. Since the film for semiconductor backsurface has a rupture elongation at 25° C. of 700% or less,unintentional stretching and rupture are prevented when the film forsemiconductor back surface is peeled from the semiconductor wafer. Thus,since the film for semiconductor back surface has a low adheringstrength, and is less likely to be stretched, the film for semiconductorback surface can exhibit good reworkability.

The film for semiconductor back surface preferably has a degree ofswelling due to ethanol of 1% by weight or more. When the film forsemiconductor back surface can be swollen to a degree in theabove-mentioned range due to ethanol, the film for semiconductor backsurface has a lower adhering strength to the semiconductor wafer, whichcan provide an improvement in easy peelability.

The film for semiconductor back surface preferably contains an acrylicresin. The film for semiconductor back surface preferably contains 50 to200 parts by weight of an inorganic filler based on 100 parts by weightof the acrylic resin. Thereby, the adhering strength and the ruptureelongation can be suitably controlled.

The present invention also relates to a dicing tape-integrated film forsemiconductor back surface including: a dicing tape including a basematerial and a pressure-sensitive adhesive layer that are laminated inthis order; and the film for semiconductor back surface laminated on thepressure-sensitive adhesive layer of the dicing tape.

The present invention also relates to a method for producing asemiconductor device using the dicing tape-integrated film forsemiconductor back surface, the method including:

bonding a semiconductor wafer onto the film for semiconductor backsurface of the dicing tape-integrated film for semiconductor backsurface;

dicing the semiconductor wafer with a cutting depth so controlled as tofall within a range overstepping one surface of the pressure-sensitiveadhesive layer that faces the film for semiconductor back surface andnot reaching another surface of the pressure-sensitive adhesive layerthat faces the base material to form a semiconductor chip;

peeling the semiconductor chip from the pressure-sensitive adhesivelayer of the dicing tape together with the film for semiconductor backsurface; and

flip chip-connecting the semiconductor chip onto an adherend.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-sectional view showing one example of thedicing-tape integrated film for semiconductor back surface according toone embodiment of the present invention; and

FIG. 2A is a schematic cross-sectional view showing one example of themethod of manufacturing a semiconductor device using the dicing-tapeintegrated film for semiconductor back surface according to oneembodiment of the preset invention.

FIG. 2B is a schematic cross-sectional view showing one example of themethod of manufacturing a semiconductor device using the dicing-tapeintegrated film for semiconductor back surface according to oneembodiment of the preset invention.

FIG. 2C is a schematic cross-sectional view showing one example of themethod of manufacturing a semiconductor device using the dicing-tapeintegrated film for semiconductor back surface according to oneembodiment of the preset invention.

FIG. 2D is a schematic cross-sectional view showing one example of themethod of manufacturing a semiconductor device using the dicing-tapeintegrated film for semiconductor back surface according to oneembodiment of the preset invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention are described with reference to thedrawings, but the invention is not limited to these embodiments.Incidentally, in the drawings in the present specification, parts whichare unnecessary for the description are not given, and some parts aremagnified or minified in order to make the description easy.

Hereinafter, an embodiment in which a film for semiconductor backsurface is laminated on a dicing tape will be mainly described. FIG. 1is a schematic cross-sectional view showing one example of a dicingtape-integrated film for semiconductor back surface according to thepresent embodiment. The film for semiconductor back surface can also besuitably utilized alone.

(Dicing Tape-Integrated Film for Semiconductor Back Surface)

As shown in FIG. 1, a dicing tape-integrated film 1 for semiconductorback surface has a configuration including: a dicing tape 3 including abase material 31 and a pressure-sensitive adhesive layer 32 formed onthe base material 31, and a film 2 for semiconductor back surface formedon the pressure-sensitive adhesive layer and being suitable for flipchip type semiconductors. As shown in FIG. 1, the dicing-tape integratedfilm for semiconductor back surface of the present invention may have aconfiguration in which the film 2 for semiconductor back surface isformed only on a portion 33 corresponding to a pasting portion of asemiconductor wafer on the pressure-sensitive adhesive layer 32 of thedicing tape 3. However, it may have a configuration in which the filmfor semiconductor back surface is formed on the entire surface of thepressure-sensitive adhesive layer 32 or it may have a configuration inwhich the film for semiconductor back surface is formed on a portionlarger than the portion 33 corresponding to the pasting portion of asemiconductor wafer and smaller than the entire surface of thepressure-sensitive adhesive layer 32. Further, the surface of the film 2for semiconductor back surface (the surface that is pasted to the backsurface of a wafer) may be protected by a separator, etc. until it ispasted to the back surface of a wafer.

(Film for Semiconductor Back Surface)

The film 2 for semiconductor back surface (see FIG. 1) has a film shape.The film 2 for semiconductor back surface is suitably used in order toprotect the back surface of a semiconductor element such as asemiconductor chip and improve the strength of the semiconductorelement. The film 2 for semiconductor back surface is usually in anuncured state (including a semi-cured state) in both a form of the filmalone and a form of the dicing tape-integrated film for semiconductorback surface. The film 2 for semiconductor back surface is thermallycured after being bonded to the semiconductor wafer.

The film for semiconductor back surface preferably has an adheringstrength (70° C., peeling angle: 180 degrees, peel rate: 300 mm/min) tothe semiconductor wafer of 7 N/10 mm or less, more preferably 0.5 N/10mm to 6.5 N/10 mm, and even more preferably 1.0 N/10 mm to 6.0 N/10 mm.When the adhering strength is set within the above-mentioned range,reworkability is improved while the adhesion of the film forsemiconductor back surface to the semiconductor wafer is maintained.

The film for semiconductor back surface preferably has a ruptureelongation at 25° C. of 700% or less, more preferably 50% or more and600% or less, and even more preferably 100% or more and 500% or less. Bysetting the rupture elongation within the above-mentioned range,unintentional stretching and rupture are prevented when the film forsemiconductor back surface is peeled from the semiconductor wafer, whichcan provide a further improvement in reworkability.

The film for semiconductor back surface preferably has a degree ofswelling due to ethanol of 1% by weight or more, more preferably 1.5% byweight or more, and even more preferably 2.0% by weight or more. Thedegree of swelling is preferably 100% by weight or less, and morepreferably 50% by weight or less. Thereby, when the film forsemiconductor back surface is peeled from the semiconductor wafer, thefilm for semiconductor back surface can be swollen due to ethanol, whichcan provide a further improvement in reworkability.

<Method for Measuring Degree of Swelling>

About 0.1 g of a sample is sampled from the film for semiconductor backsurface and precisely weighed (weight of sample) and, after the sampleis wrapped in a mesh sheet, it is immersed in about 50 mL of ethanol atroom temperature for 1 week. Thereafter, a solvent-insoluble matter(content in the mesh sheet) is taken out of ethanol and air-dried atroom temperature until the weight change reaches 1% or less. Thesolvent-insoluble matter after air drying is weighed (weight W1 afterimmersing and air drying). Then, the solvent-insoluble matter is driedby heating at 130° C. for about 2 hours, and the solvent-insolublematter after drying is weighed (weight W2 after immersing and drying byheating). A degree of swelling (% by weight) is calculated according tothe following expression (a).Degree of swelling (% by weight)=[(W1−W2)/W2]×100  (a)

The degree of swelling of the film for semiconductor back surface can becontrolled by the kind and content of the resin components and the kindand content of the crosslinking agent, and besides, heating temperature,heating time, and the like.

Preferably, the film 2 for semiconductor back surface is made from atleast a thermosetting resin, and more preferably made from at least athermosetting resin and a thermoplastic resin. A thermalcuring-accelerating catalyst may be incorporated in the resin whichconstitutes the film 2 for semiconductor back surface. When the film 2for semiconductor back surface is made from at least a thermosettingresin, the film 2 for semiconductor back surface can effectively exhibitits adhesive function.

Examples of the thermoplastic resin include a natural rubber, a butylrubber, an isoprene rubber, a chloroprene rubber, an ethylene-vinylacetate copolymer, an ethylene-acrylate copolymer, an ethylene-acrylicester copolymer, a polybutadiene resin, a polycarbonate resin, athermoplastic polyimide resin, polyamide resins such as 6-nylon and6,6-nylon, a phenoxy resin, an acrylic resin, saturated polyester resinssuch as PET (polyethylene terephthalate) and PBT (polybutyleneterephthalate), a polyamideimide resin, and a fluororesin. Thethermoplastic resins can be used alone or two types or more can be usedtogether. Of these thermoplastic resins, acrylic resin is particularlypreferable since the resin contains ionic impurities in only a smallamount and has a high heat resistance so as to make it possible toensure the reliability of the semiconductor element.

The acrylic resin is not especially limited, and examples thereofinclude a polymer having one type or two types or more of acrylates ormethacrylates having a linear or branched alkyl group having 30 or lesscarbon atoms (preferably 4 to 18 carbon atoms, further preferably 6 to10 carbon atoms, and especially preferably 8 or 9 carbon atoms) as acomponent. That is, the acrylic resin of the present invention has abroad meaning and also includes a methacrylic resin. Examples of thealkyl group include a methyl group, an ethyl group, a propyl group, anisopropyl group, an n-butyl group, a t-butyl group, an isobutyl group, apentyl group, an isopentyl group, a hexyl group, a heptyl group, a2-ethylhexyl group, an octyl group, an isooctyl group, a nonyl group, anisononyl group, a decyl group, an isodecyl group, an undecyl group, adodecyl group (a lauryl group), a tridecyl group, a tetradecyl group, astearyl group, and an octadecyl group.

Other monomers that can form the above-described acrylic resin (monomersother than an alkylester of acrylic acid or methacrylic acid having analkyl group having 30 or less carbon atoms) are not especially limited.Examples thereof include carboxyl-containing monomers such as acrylicacid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate,itaconic acid, maleic acid, fumaric acid, and crotonic acid; acidanhydride monomers such as maleic anhydride and itaconic anhydride;hydroxyl-containing monomers such as 2-hydroxyethyl (meth)acrylate,2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate,6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate,10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, and(4-hydroxymethylcyclohexyl) methylacrylate; monomers which contain asulfonic acid group, such as styrenesulfonic acid, allylsulfonic acid,2-(meth)acrylamide-2-methylpropanesulfonic acid, (meth)acrylamidepropanesulfonic acid, sulfopropyl (meth)acrylate, and(meth)acryloyloxynaphthalenesulfonic acid; and monomers which contain aphosphoric acid group, such as 2-hydroxyethylacryloyl phosphate.(Meth)acrylate refers to an acrylate and/or a methacrylate, and every“(meth)” in the present invention has the same meaning.

Examples of the thermosetting resin include an epoxy resin, a phenolresin, an amino resin, an unsaturated polyester resin, a polyurethaneresin, a silicone resin, and a thermosetting polyimide resin. Thethermosetting resins can be used alone or two types or more can be usedtogether. An epoxy resin having a small amount of ionic impurities thaterode the semiconductor element is especially suitable as thethermosetting resin. Further, a phenol resin can be suitably used as acuring agent for the epoxy resin.

The epoxy resin is not especially limited, and examples thereof includebifunctional epoxy resins and polyfunctional epoxy resins such as abisphenol A type epoxy resin, a bisphenol F type epoxy resin, abisphenol S type epoxy resin, a brominated bisphenol A type epoxy resin,a hydrogenated bisphenol A type epoxy resin, a bisphenol AF type epoxyresin, a bisphenyl type epoxy resin, a naphthalene type epoxy resin, afluorene type epoxy resin, a phenol novolak type epoxy resin, anortho-cresol novolak type epoxy resin, a trishydroxyphenylmethane typeepoxy resin, and a tetraphenylolethane type epoxy resin, a hydantointype epoxy resin, a trisglycidylisocyanurate type epoxy resin, and aglycidylamine type epoxy resin.

Among the above-described epoxy resins, a novolak type epoxy resin, abiphenyl type epoxy resin, a trishydroxyphenylmethane type epoxy resin,and a tetraphenylolethane type epoxy resin are especially preferable.These epoxy resins are highly reactive with a phenol resin as a curingagent and are excellent in heat resistance.

The phenol resin acts as a curing agent for the epoxy resin, andexamples thereof include novolak type phenol resins such as a phenolnovolak resin, a phenol aralkyl resin, a cresol novolak resin, atert-butylphenol novolak resin, and a nonylphenol novolak resin, a resoltype phenol resin, and polyoxystyrenes such as polyparaoxystyrene. Thephenol resins can be used alone or two types or more can be usedtogether. Among these phenol resins, a phenol novolak resin and a phenolaralkyl resin are especially preferable because connection reliabilityof the c can be improved.

The phenol resin is suitably compounded in the epoxy resin so that ahydroxyl group in the phenol resin to 1 equivalent of an epoxy group inthe epoxy resin component becomes 0.5 to 2.0 equivalents. The ratio ismore preferably 0.8 to 1.2 equivalents. When the compounding ratio goesout of this range, sufficient curing reaction does not proceed, and thecharacteristics of the epoxy resin cured substance easily deteriorate.

The content of the thermosetting resin is preferably 5% by weight ormore and 90% by weight or less, more preferably 10% by weight or moreand 85% by weight or less, and even more preferably 15% by weight ormore and 80% by weight or less based on all the resin components in theadhesive layer. When the content is 5% by weight or more, the shrinkagedue to thermal curing may be readily controlled to be 2% by volume ormore. In thermally curing the sealing resin, the adhesive layer may befully thermally cured so as to be surely adhered and fixed to the backsurface of a semiconductor element. Thus, a flip chip type semiconductordevice with no peeling can be produced. On the other hand, when thecontent is 90% by weight or less, the package (PKG, flip chip typesemiconductor device) may be prevented from warping.

A thermal curing accelerating catalyst for an epoxy resin and a phenolresin is not especially limited, and the catalyst can be appropriatelyselected from known thermal curing accelerating catalysts. The thermalcuring accelerating catalysts can be used alone or two types or more canbe used together. Examples of the thermal curing accelerating catalystinclude an amine curing accelerator, a phosphorus curing accelerator, animidazole curing accelerator, a boron curing accelerator and aphosphorus-boron curing accelerator.

The film for semiconductor back surface is suitably formed of a resincomposition containing an epoxy resin and a phenol resin and a resincomposition containing an epoxy resin, a phenol resin, and an acrylicresin. Because these resins have few ionic impurities and high heatresistance, reliability of the semiconductor element can be ensured.

It is important that the film 2 for semiconductor back surface hastackiness (adhesion) to the back surface (the surface where a circuit isnot formed) of a semiconductor wafer. The film 2 for semiconductor backsurface can be formed of a resin composition containing an epoxy resinas a thermosetting resin, for example. A polyfunctional compound thatreacts with a functional group of the end of the polymer molecular chainis preferably added as a crosslinking agent to crosslink the film 2 forsemiconductor back surface to some extent in advance. With thisoperation, the adhesion characteristics under high temperature can beimproved and the heat resistance can be improved.

The crosslinking agent is not especially limited, and a knowncrosslinking agent can be used. Specific examples thereof include anisocyanate crosslinking agent, an epoxy crosslinking agent, a melaminecrosslinking agent, a peroxide crosslinking agent, a urea crosslinkingagent, a metal alkoxide crosslinking agent, a metal chelate crosslinkingagent, a metal salt crosslinking agent, a carbodiimide crosslinkingagent, an oxazoline crosslinking agent, an aziridine crosslinking agent,and an amine crosslinking agent. An isocyanate crosslinking agent and anepoxy crosslinking agent are preferable. The crosslinking agents can beused alone or two type or more can be used together.

Examples of the isocyanate crosslinking agent include lower aliphaticpolyisocyanates such as 1,2-ethylene diisocyanate, 1,4-butyleneisocyanate, and 1,6-hexamethylene diisocyanate; alicyclicpolyisocyanates such as cyclopentylene diisocyanate, cyclohexylenediisocyanate, isophorone diisocyanate, hydrogenated tolylenediisocyanate, and hydrogenated xylene diisocyanate; and aromaticpolyisocyanates such as 2,4-tolylene diisocyanate, 2,6-tolylenediisocyanate, 4,4′-diphenylmethanediisocyanate, and xylylenediisiocyanate. A trimethylolpropane/tolylene diisocyanate trimer adduct(tradename: Coronate L manufactured by Nippon Polyurethane Industry Co.,Ltd.) and a trimethylolpropane/hexamethylene diisocyanate trimer adduct(tradename: Coronate HL manufactured by Nippon Polyurethane IndustryCo., Ltd.) can also be used. Examples of the epoxy crosslinking agentinclude N,N,N′,N′-tetraglycidyl-m-xylenediamine, diglycidylaniline,1,3-bis(N,N-glycidylaminomethyl)cyclohexane, 1,6-hexanedioldiglycidylether, neopentylglycol diglycidylether, ethyleneglycoldiglycidylether, propyleneglycol diglycidylether, polyethyleneglycoldiglycidylether, polypropyleneglycol diglycidylether, sorbitolpolyglycidylether, glycerol polyglycidylether, pentaerythritolpolyglycidylether, polyglyserol polyglycidylether, sorbitanpolyglycidylether, trimethylolpropane polyglycidylether, diglycidyladipate, diglycidyl o-phthalate,triglycidyl-tris(2-hydroxyethyl)isocyanurate, resorcin diglycidylether,bisphenol-s-diglycidyl ether, and an epoxy resin having two or moreepoxy groups in the molecule.

The used amount of the crosslinking agent is not especially limited, andcan be appropriately selected according to the level of crosslinking.Specifically, the used amount of the crosslinking agent is normallypreferably 7 parts by weight or less (0.05 to 7 parts by weight, forexample) to 100 parts by weight of a polymer component (especially, apolymer having a functional group at the end of the molecular chain) forexample. When the used amount of the crosslinking agent is more than 7parts by weight to 100 parts by weight of the polymer component, it isnot preferable because the adhering strength decreases. From theviewpoint of improving cohesive strength, the used amount of thecrosslinking agent is preferably 0.05 parts by weight or more to 100parts by weight of the polymer component.

In the present invention, it is possible to perform a crosslinkingtreatment by irradiation with an electron beam, an ultraviolet ray, orthe like in place of using the crosslinking agent or together with acrosslinking agent.

The film for semiconductor back surface is preferably colored. With thisconfiguration, the films for semiconductor back surface can exhibit anexcellent marking property and an excellent appearance, and asemiconductor device can be obtained having an appearance with addedvalue. Because the colored film for semiconductor back surface has anexcellent marking property, various information such as characterinformation and pattern information can be given to a semiconductordevice or the surface where a circuit is not formed of the semiconductordevice in which the semiconductor element is marked through the film forsemiconductor back surface using various marking methods such as aprinting method and a laser marking method. Especially, the informationsuch as character information and pattern information that is given bymarking can be recognized visually with excellent visibility bycontrolling the color. Because the film for semiconductor back surfaceis colored, the dicing tape and the film for semiconductor back surfacecan be easily distinguished, and workability can be improved. It ispossible to color-code the semiconductor device byproduct, for example.When the film for semiconductor back surface is colored (when it is notcolorless or transparent), the color is not especially limited. However,the color is preferably a dark color such as black, blue, or red, andblack is especially preferable.

In this embodiment, the dark color means a dark color having L* that isdefined in the L*a*b* color system of basically 60 or less (0 to 60),preferably 50 or less (0 to 50) and more preferably 40 or less (0 to40).

The black color means a blackish color having L* that is defined in theL*a*b* color system of basically 35 or less (0 to 35), preferably 30 orless (0 to 30) and more preferably 25 or less (0 to 25). In the blackcolor, each of a* and b* that is defined in the L*a*b* color system canbe appropriately selected according to the value of L*. For example,both of a* and b* are preferably −10 to 10, more preferably −5 to 5, andespecially preferably −3 to 3 (above all, 0 or almost 0).

In this embodiment, L*, a*, and b* that are defined in the L*a*b* colorsystem can be obtained by measurement using a colorimeter (tradename:CR-200 manufactured by Konica Minolta Holdings, Inc.). The L*a*b* colorsystem is a color space that is endorsed by Commission Internationale deI'Eclairage (CIE) in 1976, and means a color space that is called aCIE1976 (L*a*b*) color system. The L*a*b* color system is provided inJIS Z 8729 in the Japanese Industrial Standards.

When the film for semiconductor back surface is colored, color materials(coloring agents) may be used depending on intended color. Various darkcolor materials such as black color materials, blue color materials, andred color materials can be preferably used, and black color materialsare especially preferable. The color materials include any of pigments,dyes, etc. The color materials may be used either alone or incombination of two or more types. Further, the dyes can be used in anyform of acid dyes, reactive dyes, direct dyes, disperse dyes, cationicdyes, etc. Further, the form of the pigments is not especially limited,and it can be appropriately selected from the known pigments and used.

When dyes are used as the color materials, the films for semiconductorback surface (consequently a dicing-tape integrated film forsemiconductor back surface) having uniform or almost uniform coloringconcentration can be easily manufactured because the dyes disperseuniformly or almost uniformly due to dissolution in the films forsemiconductor back surface. Because of that, when the dyes are used asthe color materials, the coloring concentration of the film forsemiconductor back surface in the dicing tape-integrated film forsemiconductor back surface can be made uniform or almost uniform, andthe marking property and the appearance can be improved.

The black color material is not especially limited, and can beappropriately selected from inorganic black pigments and black dyes, forexample. The black color material may be a color material mixture inwhich a cyan color material (blue-green color material), a magenta colormaterial (red-purple color material), and a yellow color material aremixed together. The black color materials can be used alone or two typesor more can be used together. The black color materials can be used alsowith other color materials other than black.

Specific examples of the black color materials include carbon black suchas furnace black, channel black, acetylene black, thermal black, andlamp black, graphite (black lead), copper oxide, manganese dioxide, azopigments such as azomethine azo black, aniline black, perylene black,titanium black, cyanine black, activated carbon, ferrite such asnonmagnetic ferrite and magnetic ferrite, magnetite, chromium oxide,iron oxide, molybdenum disulfide, chromium complex, complex oxide black,and anthraquinone organic black.

In the present invention, black dyes such as C. I. solvent black 3, 7,22, 27, 29, 34, 43, and 70, C. I. direct black 17, 19, 22, 32, 38, 51,and 71, C. I. acid black 1, 2, 24, 26, 31, 48, 52, 107, 109, 110, 119,and 154, and C. I. disperse black 1, 3, 10, and 24; and black pigmentssuch as C. I. pigment black 1 and 7 can be used as the black colormaterial.

For example, trade name “Oil Black BY”, trade name “Oil Black BS”, tradename “Oil Black HBB”, trade name “Oil Black 803”, trade name “Oil Black860”, trade name “Oil Black 5970”, trade name “Oil Black 5906” and tradename “Oil Black 5905” (manufactured by Orient Chemical Industries Co.,Ltd.) and so on are commercially available as the black color material.

Examples of color materials other than the black color materials includea cyan color material, a magenta color material, and a yellow colormaterial. Examples of the cyan color material include cyan dyes such asC. I. solvent blue 25, 36, 60, 70, 93, and 95; and C. I. acid blue 6 and45; and cyan pigments such as C. I. pigment blue 1, 2, 3, 15, 15:1,15:2, 15:3, 15:4, 15:5, 15:6, 16, 17, 17:1, 18, 22, 25, 56, 60, 63, 65,and 66; C. I. vat blue 4 and 60; and C. I. pigment green 7.

Examples of the magenta color material include magenta dyes such as C.I. solvent red 1, 3, 8, 23, 24, 25, 27, 30, 49, 52, 58, 63, 81, 82, 83,84, 100, 109, 111, 121, and 122; C. I. disperse red 9; C. I. solventviolet 8, 13, 14, 21, and 27; C. I. disperse violet 1; C. I. basic red1, 2, 9, 12, 13, 14, 15, 17, 18, 22, 23, 24, 27, 29, 32, 34, 35, 36, 37,38, 39, and 40; and C. I. basic violet 1, 3, 7, 10, 14, 15, 21, 25, 26,27, and 28.

Examples of the magenta color material include magenta pigments such asC. I. pigment red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 39, 40, 41, 42, 48:1, 48:2,48:3, 48:4, 49, 49:1, 50, 51, 52, 52:2, 53:1, 54, 55, 56, 57:1, 58, 60,60:1, 63, 63:1, 63:2, 64, 64:1, 67, 68, 81, 83, 87, 88, 89, 90, 92, 101,104, 105, 106, 108, 112, 114, 122, 123, 139, 144, 146, 147, 149, 150,151, 163, 166, 168, 170, 171, 172, 175, 176, 177, 178, 179, 184, 185,187, 190, 193, 202, 206, 207, 209, 219, 222, 224, 238, and 245; C. I.pigment violet 3, 9, 19, 23, 31, 32, 33, 36, 38, 43, and 50; and C. I.vat red 1, 2, 10, 13, 15, 23, 29, and 35.

Examples of the yellow color material include yellow dyes such as C. I.solvent yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, and 162;and yellow pigments such as C. I. pigment orange 31 and 43, C. I.pigment yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17, 23,24, 34, 35, 37, 42, 53, 55, 65, 73, 74, 75, 81, 83, 93, 94, 95, 97, 98,100, 101, 104, 108, 109, 110, 113, 114, 116, 117, 120, 128, 129, 133,138, 139, 147, 150, 151, 153, 154, 155, 156, 167, 172, 173, 180, 185,and 195, and C. I. vat yellow 1, 3, and 20.

Various color materials such as cyan color materials, magenta colormaterials, and yellow color materials can be used alone or two types ormore can be used together. When two types or more of various colormaterials such as cyan color materials, magenta color materials, andyellow color materials are used, the mixing ratio or the compoundingratio of these color materials is not especially limited, and can beappropriately selected according to the types of each color material andthe intended color.

When the film 2 for semiconductor back surface is colored, the coloredform is not particularly limited. The film for semiconductor backsurface may be, for example, a single-layer film-shaped articlecontaining a coloring agent. The film may be a laminated film includingat least a resin layer made from at least a thermosetting resin and acoloring agent layer. When the film 2 for semiconductor back surface isa laminated film of the resin layer and the coloring agent layer, thefilm 2 for semiconductor back surface in the laminated form preferablyhas a laminated form of a resin layer/a coloring agent layer/a resinlayer. In this case, two resin layers at both sides of the coloringagent layer may be resin layers having the same composition or may beresin layers having different compositions.

Other additives can be appropriately compounded in the film 2 forsemiconductor back surface as necessary. Examples of the other additivesinclude a filler, a flame retardant, a silane coupling agent, an iontrapping agent, an extender, an anti-aging agent, an antioxidant, and asurfactant.

The filler may be any of an inorganic filler and an organic filler.However, an inorganic filler is preferable. By adding a filler such asan inorganic filler, electric conductivity can be given to the film forsemiconductor back surface, heat conductivity can be improved, and theelastic modulus can be adjusted. The film 2 for semiconductor backsurface may be electrically conductive or non-conductive. Examples ofthe inorganic filler include ceramics such as silica, clay, gypsum,calcium carbonate, barium sulfate, alumina oxide, beryllium oxide,silicon carbide, and silicon nitride, metals such as aluminum, copper,silver, gold, nickel, chromium, lead, tin, zinc, palladium, and solder,alloys, and various inorganic powders consisting of carbon. The fillersmay be used alone or two types or more can be used together. Amongthese, silica, especially molten silica is preferable. The averageparticle size of the inorganic filler is preferably in a range of 0.1 to80 μm. The average particle size of the inorganic filler is measuredwith a laser diffraction type particle size distribution device.

When the film for semiconductor back surface contains the acrylic resin,the amount of the filler (in particular, an inorganic filler) blended ispreferably 50 parts by weight to 200 parts by weight, and morepreferably 60 parts by weight to 180 parts by weight based on 100 partsby weight of the acrylic resin.

Examples of the flame retardant include antimony trioxide, antimonypentoxide, and a brominated epoxy resin. These can be used alone or twotypes or more can be used together. Examples of the silane couplingagent include β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane,γ-glycidoxypropyltrimethoxysilane, andγ-glycidoxypropylmethyldiethoxysilane. These compounds can be used aloneor two types or more can be used together. Examples of the ion trapagent include hydrotalcites and bismuth hydroxide. These can be usedalone or two types or more can be used together.

The film 2 for semiconductor back surface can be formed by a commonmethod of preparing a resin composition by mixing a thermosetting resinsuch as an epoxy resin, a thermoplastic resin such as an acrylic resinas necessary, and a solvent and other additives as necessary and formingthe resin composition into a film-like layer.

When the film 2 for semiconductor back surface is formed of a resincomposition containing a thermosetting resin such as an epoxy resin, thethermosetting resin in the film for semiconductor back surface isuncured or is partially cured at the stage before application to asemiconductor wafer. In this case, the thermosetting resin in the filmfor semiconductor back surface is completely cured or almost completelycured after application to a semiconductor wafer (normally when curing asealing material in a flip-chip bonding step).

When the film for semiconductor back surface in the present invention isa film that is formed with a resin composition containing athermosetting resin such as an epoxy resin, adhesion to a semiconductorwafer can be exhibited effectively.

Since cutting water is used in the dicing step of the semiconductorwafer, the film for semiconductor back surface absorbs moisture to havea moisture content more than usual in some cases. When flip chip bondingis performed with such a high moisture content, water vapor remains atthe adhesion interface between the film 2 for semiconductor back surfaceand the semiconductor wafer or a processed product thereof(semiconductor) and lifting is generated in some cases. Therefore, byusing a film for semiconductor back surface having a configuration inwhich a core material having high moisture permeability is provided oneach surface thereof, water vapor diffuses and thus it becomes possibleto avoid such a problem. From such a viewpoint, a multilayered structurein which the films 2 and 12 for semiconductor back surface are formed onone surface or both surfaces of the core material may be used as thefilm for semiconductor back surface. Examples of the core materialinclude films (e.g., polyimide films, polyester films, polyethyleneterephthalate films, polyethylene naphthalate films, and polycarbonatefilms), resin substrates reinforced with a glass fiber or a plasticnonwoven fiber, silicon substrates, and glass substrates.

The thickness of the film 2 for semiconductor back surface (totalthickness in the case of a laminated film) is not especially limited.However, it can be appropriately selected from a range of about 2 μm to200 μm. The thickness is preferably about 4 μm to 160 μm, morepreferably about 6 μm to 100 μm, and especially preferably about 10 μmto 80 μm.

The tensile storage modulus at 23° C. of the uncured film 2 forsemiconductor back surface is preferably 1 GPa or more (1 to 50 GPa, forexample), more preferably 2 GPa or more, and especially preferably 3 GPaor more. When the tensile storage modulus is 1 GPa or more, adhesion ofthe film for semiconductor back surface to a support can be effectivelysuppressed or prevented when a semiconductor chip is peeled from thepressure-sensitive adhesive layer 32 of a dicing tape together with thefilm 2 for semiconductor back surface and the film 2 for semiconductorback surface mounted on the support are transported. Examples of thesupport include a top tape and a bottom tape of a carrier tape. When thefilm 2 for semiconductor back surface is made from a resin compositioncontaining a thermosetting resin, as described above, the thermosettingresin is usually in an uncured or partially cured state, so that theelastic modulus of the film for semiconductor back surface at 23° C. isusually an elastic modulus at 23° C. in a state where the thermosettingresin is uncured or partially cured.

Here, the film 2 for semiconductor back surface may be either a singlelayer film or a laminated film including a plurality of layers. In thecase of the laminated film, the tensile storage elastic modulus at 23°C. in an uncured state should be 1 GPa or more (e.g., 1 GPa to 50 GPa)as the whole laminated film. The tensile storage elastic modulus (23°C.) of the film for semiconductor back surface in an uncured state canbe controlled by the kind and content of the resin components(thermoplastic resin and thermosetting resin) or the kind and content ofa filler such as a silica filler. When the film 2 for semiconductor backsurface is a laminated film in which a plurality of layers are laminated(when the film for semiconductor back surface has a form of laminatedlayers), an example of the form of laminated layers includes a form oflaminated layers consisting of a wafer adhesion layer and a lasermarking layer. Other layers such as an intermediate layer, a light beamshielding layer, a reinforcing layer, a coloring agent layer, a baselayer, an electromagnetic wave shielding layer, a heat conducting layer,and a pressure-sensitive adhesive layer may be provided between thewafer adhesion layer and the laser marking layer. The wafer adhesionlayer is a layer having excellent adhesion (tackiness) to a wafer andcontacting with the back surface of the wafer. The laser marking layeris a layer having an excellent laser marking property and is used toperform laser marking on the back surface of a semiconductor chip.

The uncured films 2 for semiconductor back surface is produced withoutlaminating the films on the dicing tape 3, and the tensile storagemodulus is measured using a dynamic viscoelasticity measurementapparatus (Solid Analyzer RS A2) manufactured by Rheometric ScientificFE, Ltd. in tensile mode, sample width 10 mm, sample length 22.5 mm,sample thickness 0.2 mm, frequency 1 Hz, temperature rise rate 10°C./min, under a nitrogen atmosphere, and at a prescribed temperature(23° C.)

Preferably, the film 2 for semiconductor back surface is protected witha separator (release liner) on at least one surface thereof (not shownin the drawings). For example, in the case of the dicing tape-integratedfilm 1 for semiconductor back surface, a separator may be provided ononly one surface of the film for semiconductor back surface. On theother hand, in the case of the film for semiconductor back surface notintegrated with a dicing tape, a separator may be provided on onesurface or both surfaces of the film for semiconductor back surface. Theseparator has a function as a protective material for protecting thefilm for semiconductor back surface until the film is practically used.In the case of the dicing tape-integrated film 1 for semiconductor backsurface, the separator may further serve as a supporting base materialin transferring the film 2 for semiconductor back surface onto thepressure-sensitive adhesive layer 32 on the base material of the dicingtape. The separator is peeled when pasting the semiconductor wafer ontothe film for semiconductor back surface. Examples of the separatorinclude polyethylene, polypropylene, a plastic film such as polyethyleneterephthalate whose surface is coated with a release agent such as afluorine release agent or a long chain alkylacrylate release agent, andpaper. The separator can be formed by a conventionally known method. Thethickness of the separator is also not especially limited.

When the film 2 for semiconductor back surface is not laminated on thedicing tape 3, in a state where the film 2 for semiconductor backsurface is wound into a roll along with one separator having a releaselayer on both surfaces thereof, the film 2 may be protected with theseparator having a release layer on both surfaces thereof, or the film 2may be protected with a separator having a release layer on at least onesurface thereof.

The light transmittance (visible light transmittance) of visible light(having a wavelength of 400 to 800 nm) in the film 2 for semiconductorback surface is not especially limited, and is preferably in a range of20% or less (0 to 20%), more preferably 10% or less (0 to 10%), andespecially preferably 5% or less (0 to 5%). When the visible lighttransmittance of the film 2 for semiconductor back surface is largerthan 20%, there is a fear that a bad influence may be given to thesemiconductor element when the light beam passes. The visible lighttransmittance (%) can be controlled by the type and the content of theresin component of the film 2 for semiconductor back surface, the typeand the content of the coloring agent such as a pigment or a dye, thecontent of the inorganic filler, and the like.

The visible light transmittance (%) of the film for semiconductor backsurface can be measured as follows. That is, a film for semiconductorback surface having a thickness (average thickness) of 20 μm isproduced. The film 2 for semiconductor back surface is then irradiatedwith visible light having a wavelength of 400 to 800 nm (a visible lightgenerator “ABSORPTION SPECTRO PHOTOMETER” manufactured by ShimadzuCorporation) at a prescribed intensity, and the intensity of thetransmitted visible light beam is measured. The visible lighttransmittance can be obtained from a change of the intensity before andafter the visible light beam transmits through the film 2 forsemiconductor back surface. It is also possible to obtain the visiblelight transmittance (%; wavelength: 400 to 800 nm) of the film 2 forsemiconductor back surface having a thickness of 20 μm from the visiblelight transmittance (%; wavelength: 400 to 800 nm) of the film 2 forsemiconductor back surface whose thickness is not 20 μm. The visiblelight transmittance (%) of the film 2 for semiconductor back surfacehaving a thickness of 20 μm is obtained in the present invention.However, the thickness of the film for semiconductor back surfaceaccording to the present invention is not limited to 20 μm.

The coefficient of moisture absorption of the film 2 for semiconductorback surface is preferably low. Specifically, the coefficient ofmoisture absorption is preferably 1% by weight or less, and morepreferably 0.8% by weight or less. By making the coefficient of moistureabsorption 1% by weight or less, the laser marking property can beimproved. Further, generation of voids between the film 2 forsemiconductor back surface and the semiconductor element can besuppressed or prevented in a reflow step, for example. The coefficientof moisture absorption is a value calculated from the weight changebefore and after the film 2 for semiconductor back surface are leftunder an atmosphere of a temperature of 85° C. and a relative humidityof 85% RH for 168 hours. When the film 2 for semiconductor back surfaceare formed of a resin composition containing a thermosetting resin, thecoefficient of moisture absorption is a value obtained the films forsemiconductor back surface after thermal curing are left under anatmosphere of a temperature of 85° C. and a relative humidity of 85% RHfor 168 hours. The coefficient of moisture absorption can be adjusted bychanging the added amount of the inorganic filler, for example.

The ratio of the volatile component of the film 2 for semiconductor backsurface is preferably small. Specifically, the weight decrease rate(ratio of the weight decrease amount) of the film 2 for semiconductorback surface after a heat treatment is preferably 1% by weight or less,and more preferably 0.8% by weight or less. The condition of the heatingtreatment is a heating temperature of 250° C. and a heating time of 1hour, for example. By making the weight decrease rate 1% by weight orless, the laser marking property can be improved. The generation ofcracks in the flip-chip type semiconductor device can be suppressed orprevented in a reflow step, for example. The weight decrease rate can beadjusted by adding an inorganic substance that can decrease thegeneration of cracks during a lead free solder reflow, for example. Whenthe film 2 for semiconductor back surface is formed with a resincomposition containing a thermosetting resin, the weight decrease ratemeans a value obtained when the film for semiconductor back surfaceafter thermal curing is heated under conditions of a heating temperatureof 250° C. and a heating time of 1 hour.

(Dicing Tape)

The dicing tape 3 has a configuration in which the pressure-sensitiveadhesive layer 32 is formed on the base material 31. As described above,the dicing tape 3 may have a configuration in which the base material 31and the pressure-sensitive adhesive layer 32 are laminated.

(Base Material)

The base material (supporting base material) can be used as a supportbase body of the pressure-sensitive adhesive layer, and the like. Thebase material 31 preferably has radiation transparency. Examples of thebase material 31 include appropriate thin materials including paper basematerials such as paper; fiber base materials such as cloth, unwovencloth, felt, and net; metal base materials such as a metal foil and ametal plate; plastic base materials such as a plastic film and sheet;rubber base materials such as a rubber sheet; foams such as a foamedsheet, and laminated bodies of these (especially laminated bodies of aplastic base and other base materials and laminated bodies of plasticfilms or sheets). In the present invention, a plastic base material suchas a plastic film or sheet can be preferably used as the base material.Examples of the material of such a plastic base material include olefinresins such as polyethylene (PE), polypropylene (PP), and anethylene-propylene copolymer; copolymers having ethylene as a monomercomponent such as a ethylene vinyl acetate copolymer (EVA), an ionomerresin, a ethylene-(meth)acrylate copolymer, and anethylene-(meth)acrylate (random, alternating) copolymer; polyesters suchas polyethylene terephthalate (PET), polyethylene naphthalate (PEN), andpolybutylene terephthalate (PBT); an acrylic resin; polyvinyl chloride(PVC); polyurethane; polycarbonate; polyphenylene sulfide (PPS); amideresins such as polyamide (nylon) and fully aromatic polyamide (aramid);polyether ether ketone (PEEK); polyimide; polyetherimide; polyvinylidenechloride; ABS (acrylonitrile-butadiene-styrene copolymer); a celluloseresin; a silicone resin; and a fluororesin.

Further, the material of the base material 31 includes a polymer such asa cross-linked body of the above resins. The above plastic film may bealso used unstretched, or may be also used on which a monoaxial or abiaxial stretching treatment is performed depending on necessity.According to resin sheets in which heat shrinkable properties are givenby the stretching treatment, etc., the adhesive area of thepressure-sensitive adhesive layer 32 and the film 2 for semiconductorback surface are reduced by thermally shrinking the base material 31after dicing, and the recovery of the semiconductor chips (asemiconductor element) can be facilitated.

A known surface treatment such as a chemical or physical treatment suchas a chromate treatment, ozone exposure, flame exposure, high voltageelectric exposure, and an ionized ultraviolet treatment, and a coatingtreatment by an undercoating agent (for example, a tacky substancedescribed later) can be performed on the surface of the base material 31in order to improve adhesiveness, holding properties, etc. with theadjacent layer.

The same type or different types can be appropriately selected and usedas the base material 31, and several types can be blended and used asnecessary. A vapor deposited layer of a conductive substance having athickness of about 30 to 500 Å consisting of metals, alloys, and oxidesof these can be provided on the base material 31 to give an antistaticfunction to the base material 31. The base material 31 may be a singlelayer or a multilayer consisting of two types or more layers.

The thickness of the base material 31 (total thickness in the case of alaminated body) is not especially limited, and can be appropriatelyselected according to the strength, flexibility, purpose of use, and thelike. For example, the thickness is generally 1000 μm less (1 to 1000μm, for example), preferably 10 to 500 μm, more preferably 20 to 300 μm,and especially preferably about 30 to 200 μm. However, the thickness isnot limited to these ranges.

The base material 31 may contain various additives such as a coloringagent, a filler, a plasticizer, an anti-aging agent, an antioxidant, asurfactant, and a flame retardant as long as the effects of the presentinvention are not deteriorated.

(Pressure-Sensitive Adhesive Layer)

The pressure-sensitive adhesive layer 32 is formed with apressure-sensitive adhesive, and has adherability. Thepressure-sensitive adhesive is not especially limited, and can beappropriately selected among known pressure-sensitive adhesives.Specifically, known pressure-sensitive adhesives (refer to JapanesePatent Application Laid-Open Nos. 56-61468, 61-174857, 63-17981, and56-13040, for example) such as a pressure-sensitive adhesive having theabove-described characteristics can be appropriately selected from anacrylic pressure-sensitive adhesive, a rubber pressure-sensitiveadhesive, a vinylalkylether pressure-sensitive adhesive, a siliconepressure-sensitive adhesive, a polyester pressure-sensitive adhesive, apolyamide pressure-sensitive adhesive, a urethane pressure-sensitiveadhesive, a fluorine pressure-sensitive adhesive, a styrene-diene blockcopolymer pressure-sensitive adhesive, and a creep property improvedpressure-sensitive adhesive in which a hot-melt resin having a meltingpoint of about 200° C. or less is compounded in these pressure-sensitiveadhesives. A radiation curing type pressure-sensitive adhesive (or anenergy ray curing type pressure-sensitive adhesive) and a thermallyexpandable pressure-sensitive adhesive can also be used as thepressure-sensitive adhesive. The pressure-sensitive adhesives can beused alone or two types or more can be used together.

An acrylic pressure-sensitive adhesive and a rubber pressure-sensitiveadhesive can be suitably used as the pressure-sensitive adhesive, andespecially an acrylic pressure-sensitive adhesive is suitable. Anexample of the acrylic pressure-sensitive adhesive is an acrylicpressure-sensitive adhesive having an acrylic polymer, in which one typeor two types or more of alkyl (meth)acrylates are used as a monomercomponent, as a base polymer.

Examples of alkyl (meth)acrylates in the acrylic pressure-sensitiveadhesive include methyl (meth)acrylate, ethyl (meth)acrylate, propyl(meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl(meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl(meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl(meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate,nonyl(meth)acrylate, isononyl(meth)acrylate, decyl (meth)acrylate,isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate,tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl(meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate,octadecyl (meth)acrylate, nonadecyl (meth)acrylate, and eicosyl(meth)acrylate. Alkyl (meth)acrylates having an alkyl group of 4 to 18carbon atoms is suitable. The alkyl group of alkyl (meth)acrylates maybe any of linear or branched chain.

The acrylic polymer may contain units that correspond to other monomercomponents that is copolymerizable with alkyl (meth)acrylates describedabove (copolymerizable monomer component) for reforming cohesivestrength, heat resistance, and crosslinking property, as necessary.Examples of such copolymerizable monomer components include carboxylgroup-containing monomers such as (meth)acrylic acid (acrylic acid,methacrylic acid), carboxyethyl acrylate, carboxypentyl acrylate,itaconic acid, maleic acid, fumaric acid, and crotonic acid; acidanhydride group-containing monomers such as maleic anhydride anditaconic anhydride; hydroxyl group-containing monomers such ashydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl(meth)acrylate, hydroxyhexyl (meth)acrylate, hydroxyoctyl(meth)acrylate, hydroxydecyl (meth)acrylate, hydroxylauryl(meth)acrylate, and (4-hydroxymethylcyclohexyl)methyl methacrylate;sulfonate group-containing monomers such as styrenesulfonic acid,allylsulfonic acid, 2-(meth)acrylamide-2-methylpropanesulfonic acid,(meth)acrylamidepropanesulfonic acid, sulfopropyl(meth)acrylate, and(meth)acryloyloxynaphthalenesulfonic acid; phosphate group-containingmonomers such as 2-hydroxyethylacryloylphosphate; (N-substituted) amidemonomers such as (meth)acrylamide, N,N-dimethyl(meth)acrylamide,N-butyl(meth)acrylamide, N-methylol(meth)acrylamide, andN-methylolpropane(meth)acrylamide; aminoalkyl (meth)acrylate monomerssuch as aminoethyl (meth)acrylate, N,N-dimethylaminoethyl(meth)acrylate, and t-butylaminoethyl (meth)acrylate; alkoxyalkyl(meth)acrylate monomers such as methoxyethyl (meth)acrylate andethoxyethyl (meth)acrylate; cyanoacrylate monomers such as acrylonitrileand methacrylonitrile; epoxy group-containing acrylic monomers such asglycidyl (meth)acrylate; styrene monomers such as styrene andα-methylstyrene; vinylester monomers such as vinyl acetate and vinylpropionate; olefin monomers such as isoprene, butadiene, andisobutylene; vinylether monomers such as vinylether; nitrogen-containingmonomers such as N-vinylpyrrolidone, methylvinylpyrrolidone,vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine,vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole,vinylmorpholine, N-vinylcarboxylic acid amides, and N-vinylcaprolactam;maleimide monomers such as N-cyclohexylmaleimide, N-isopropylmaleimide,N-laurylmaleimide, and N-phenylmaleimide; itaconimide monomers such asN-methylitaconimide, N-ethylitaconimide, N-butylitaconimide,N-octylitaconimide, N-2-ethylhexylitaconimide, N-cyclohexylitaconimide,and N-laurylitaconimide; succinimide monomers such asN-(meth)acryloyloxymethylene succinimide,N-(meth)acryloyl-6-oxyhexamethylene succinimide, andN-(meth)acryloyl-8-oxyoctamethylene succinimide; glycol acrylestermonomers such as polyethylene glycol (meth)acrylate, polypropyleneglycol (meth)acrylate, metoxyethylene glycol (meth)acrylate, andmetoxypolypropylene glycol (meth)acrylate; acrylate monomers having aheterocyclic ring, a halogen atom, a silicon atom, and the like such astetrahydrofurfuryl (meth)acrylate, fluorine (meth)acrylate, and silicone(meth)acrylate; and polyfunctional monomers such as hexanedioldi(meth)acrylate, (poly)ethylene glycol di(meth)acrylate,(poly)propylene glycol di(meth)acrylate, neopentyl glycoldi(meth)acrylate, pentaerythritol di(meth)acrylate, trimethylolpropanetri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritolhexa(meth)acrylate, epoxyacrylate, polyesteracrylate, urethaneacrylate,divinylbenzene, butyl di(meth)acrylate, and hexyl di(meth)acrylate. Onetype or two types or more of these copolymerizable monomer componentscan be used.

When a radiation curing type pressure-sensitive adhesive (or an energyray curing type pressure-sensitive adhesive) is used as thepressure-sensitive adhesive, examples of the radiation curing typepressure-sensitive adhesive (composition) include an internal radiationcuring type pressure-sensitive adhesive having a polymer with a radicalreactive carbon-carbon double bond in the polymer side chain, the mainchain, or the ends of the main chain as a base polymer and a radiationcuring type pressure-sensitive adhesive in which ultraviolet-raycuring-type monomer component and oligomer component are compounded inthe pressure-sensitive adhesive. When a thermally expandablepressure-sensitive adhesive is used as the pressure-sensitive adhesive,examples thereof include a thermally expandable pressure-sensitiveadhesive containing a pressure-sensitive adhesive and a foaming agent(especially, a thermally expandable microsphere).

The pressure-sensitive adhesive layer 32 of the present invention maycontain various additives such as a tackifier, a coloring agent, athickener, an extender, a filler, a plasticizer, an anti-aging agent, anantioxidant, a surfactant, and a crosslinking agent as long as theeffects of the present invention are not deteriorated.

The crosslinking agent is not especially limited, and known crosslinkingagents can be used. Specific examples of the crosslinking agent includean isocyanate crosslinking agent, an epoxy crosslinking agent, amelamine crosslinking agent, a peroxide crosslinking agent, a ureacrosslinking agent, a metal alkoxide crosslinking agent, a metal chelatecrosslinking agent, a metal salt crosslinking agent, a carbodiimidecrosslinking agent, an oxazoline crosslinking agent, an aziridinecrosslinking agent, and an amine crosslinking agent, and an isocyanatecrosslinking agent and an epoxy crosslinking agent are preferable. Thecrosslinking agents can be used alone or two types or more can be usedtogether. The used amount of the crosslinking agent is not especiallylimited.

Examples of the isocyanate crosslinking agent include lower aliphaticpolyisocyanates such as 1,2-ethylene diisocyanate, 1,4-butylenediisocyanate, and 1,6-hexamethylene diisocyanate; alicyclicpolyisocyanates such as cyclopentylene diisocyanate, cyclohexylenediisocyanate, isophorone diisocyanate, hydrogenated tolylenediisocyanate, and hydrogenated xylene diisocyanate; and aromaticpolyisocyanates such as 2,4-tolylene diisocyanate, 2,6-tolylenediisocyanate, 4,4′-diphenylmethane diisocyanate, and xylylenediisocyanate. A trimethylolpropane/tolylene diisocyanate trimeric adduct(Coronate L manufactured by Nippon Polyurethane Industry Co., Ltd.), anda trimethylolpropane/hexamethylene diisocyanate trimeric adduct(Coronate HL manufactured by Nippon Polyurethane Industry Co., Ltd.) canalso be used. Examples of the epoxy crosslinking agent includeN,N,N′,N′-tetraglycidyl-m-xylenediamine, diglycidylaniline,1,3-bis(N,N-glycidylaminomethyl)cyclohexane, 1,6-hexanedioldiglycidylether, neopentylglycol diglycidylether, ethyleneglycoldiglycidylether, propyleneglycol diglycidylether, polyethyleneglycoldiglycidylether, polypropyleneglycol diglycidylether, sorbitolpolyglycidylether, glycerol polyglycidylether, pentaerithritolpolyglycidylether, polyglycerol polyglycidylether, sorbitanpolyglycidylether, trimethylolpropane polyglycidylether, diglycidyladipate, o-diglycidyl phthalate,triglycidyl-tris(2-hydroxyethyl)isocyanurate, resorcin diglycidylether,bisphenol-S-diglycidylether; and an epoxy resin having two or more epoxygroups in a molecule.

In the present invention, a crosslinking treatment can be performed byirradiation with an electron beam, an ultraviolet ray, or the likeinstead of using the crosslinking agent or in addition to the use of thecrosslinking agent.

The pressure-sensitive adhesive layer 32 can be formed by a commonmethod of forming a sheet-like layer by mixing the pressure-sensitiveadhesive with a solvent, other additives, and the like as necessary.Specifically, the pressure-sensitive adhesive layer 32 can be producedby a method of applying the pressure-sensitive adhesive or a mixturecontaining the pressure-sensitive adhesive, a solvent and otheradditives to the base material 31, a method of forming thepressure-sensitive adhesive layer 32 by applying the above-describedmixture to an appropriate separator (release paper, for example), andtransferring (adhering) the resultant onto the base material 31, forexample.

The thickness of the pressure-sensitive adhesive layer 32 is notparticularly limited. For example, the thickness is 5 μm or more and 200μm or less, preferably 5 μm or more and 50 μm or less, more preferably 5μm or more and 45 μm or less, and particularly preferably 5 μm or moreand 40 μm or less. When the thickness of the pressure-sensitive adhesivelayer 32 falls within the above range, the layer may exhibit a suitableadhesive strength, which can provide a sufficient improvement intackiness between the base material and the pressure-sensitive adhesivelayer, and secure the holding force of the semiconductor wafer duringdicing. The pressure-sensitive adhesive layer 32 may be either a singlelayer or a multilayer.

The adhering strength (23° C., peeling angle: 180 degrees, peel rate:300 mm/min) of the pressure-sensitive adhesive layer 32 of the dicingtape 3 to the film 2 for semiconductor back surface is preferably 0.02N/20 mm to 10 N/20 mm, and more preferably 0.05 N/20 mm to 5 N/20 mm.When the adhering strength is 0.02 N/20 mm or more, the semiconductorelements can be prevented from chip scattering in dicing a semiconductorwafer. On the other hand, when the adhering strength is 10 N/20 mm orless, the semiconductor elements are difficult to be peeled in beingpicked up, and the adhesive residue is prevented.

In the present invention, an antistatic function can be given to thefilm 2 for semiconductor back surface or the dicing-tape integrated film1 for semiconductor back surface. With this configuration, generation ofstatic electricity on the films during adhesion and peeling and damagesof the circuit due to electrification of the semiconductor wafer, andthe like can be prevented. The antistatic function can be given by anappropriate method such as a method of adding an antistatic agent or aconductive substance to the base material 31, the pressure-sensitiveadhesive layer 32, or the film 2 for semiconductor back surface and amethod of providing a conductive layer made of a charge-transfer complexor a metal film to the base material 31. A method of giving theantistatic function is preferable with which impurity ions that candeteriorate the semiconductor wafer are hardly generated. Examples ofthe conductive substance (conductive filler) that is compounded to giveelectric conductivity and to improve heat conductivity includespherical, needle-like, and flaky metal powders of silver, aluminum,gold, copper, nickel, and conductive alloys, metal oxides of alumina,amorphous carbon black, and graphite. However, the film 2 forsemiconductor back surface is preferably electrically non-conductivefrom the viewpoint of making the films have no electrical leakage.

The film 2 for semiconductor back surface and the dicing tape-integratedfilm 1 for semiconductor back surface may be formed in a form in whichthe films are wound into a roll or a form in which the sheets (films)are laminated. When the films have a form in which they are wound into aroll, the film 2 for semiconductor back surface or the dicingtape-integrated film 1 for semiconductor back surface having a state orform in which the films are wound into a roll can be produced by windingthe film 2 for semiconductor back surface or a laminate of the film 2for semiconductor back surface and the dicing tape 3 into a roll withthe film or the laminate being protected with a separator as necessary.The dicing tape-integrated film 1 for semiconductor back surface whichis wound into a roll may include the base material 31, thepressure-sensitive adhesive layer 32 which is formed on one surface ofthe base material 31, a film for semiconductor back surface which isformed on the pressure-sensitive adhesive layer 32, and arelease-treated layer (back surface-treated layer) which is formed onthe other surface of the base material 31.

The thickness of the dicing tape-integrated film 1 for semiconductorback surface (total of the thickness of the film for semiconductor backsurface and the thickness of the dicing tape including the base material31 and the pressure-sensitive adhesive layer 32) can be, for example,selected from the range of 25 μm to 1,600 μm, and it is preferably 30 μmto 850 μm, more preferably 35 μm to 500 μm, and particularly preferably50 μm to 330 μm.

In the dicing tape-integrated film 1 for semiconductor back surface, bycontrolling the ratio of the thickness of the film 2 for semiconductorback surface to the thickness of the pressure-sensitive adhesive layer32 of the dicing tape 3 or the ratio of the thickness of the film 2 forsemiconductor back surface to the thickness of the dicing tape 3 (totalthickness of the base material 31 and the pressure-sensitive adhesivelayer 32), a dicing property in the dicing step and a pick up propertyin the picking-up step can be improved, and the dicing tape-integratedfilm 1 for semiconductor back surface can be effectively utilized fromthe dicing step of the semiconductor wafer to the flip chip bonding stepof the semiconductor chip.

(Method of Producing Dicing Tape-Integrated Film for Semiconductor BackSurface)

A method of producing the dicing tape-integrated film for semiconductorback surface according to this embodiment is explained using the dicingtape-integrated film 1 for semiconductor back surface shown in FIG. 1 asan example. First, the base material 31 can be formed by aconventionally known film forming method. Examples of the film formingmethod include a calender film forming method, a casting method in anorganic solvent, an inflation extrusion method in a closed system, a Tdie extrusion method, a co-extrusion method, and a dry laminatingmethod.

The pressure-sensitive adhesive layer 32 is formed by applying apressure-sensitive adhesive composition to the base material 31 anddrying the composition (by crosslinking by heat as necessary). Examplesof the application method include roll coating, screen coating, andgravure coating. The pressure-sensitive adhesive layer 32 may be formedon the base material 31 by applying the pressure-sensitive adhesivecomposition directly to the base material 31, or the pressure-sensitiveadhesive layer 32 may be transferred to the base material 31 after thepressure-sensitive adhesive layer 32 is formed by applying thepressure-sensitive adhesive composition to a release paper whose surfacehas been subjected to a release treatment. With this configuration, thedicing tape 3 is produced in which the pressure-sensitive adhesive layer32 is formed on the base material 31.

On the other hand, a formation material for forming the film 2 forsemiconductor back surface is applied onto release paper so that thethickness after drying becomes prescribed thickness, and then, it isdried under a prescribed condition (drying by carrying out a heatingtreatment when thermal curing is necessary, etc.) to forma coatinglayer. This coating layer is transferred onto the pressure-sensitiveadhesive layer 32 to form the film 2 for semiconductor back surface onthe pressure-sensitive adhesive layer 32. Further, a formation materialfor forming the film 2 for semiconductor back surface is applieddirectly onto the pressure-sensitive adhesive layer 32, and it is driedunder a prescribed condition (drying by carrying out a heating treatmentwhen thermal curing is necessary, etc.) also to form the film 2 forsemiconductor back surface on the pressure-sensitive adhesive layer 32.With this, the dicing-tape integrated film 1 for semiconductor backsurface according to the present invention can be obtained. When thermalcuring is performed to form the film 2 for semiconductor back surface,it is important to perform thermal curing up to a level at which thefilm is partially cured. However, it is preferable not to performthermal curing.

The dicing tape-integrated film 1 for semiconductor back surface can beused suitably in the manufacture of a semiconductor device having aflip-chip connecting step. The dicing tape-integrated film 1 forsemiconductor back surface of the present invention is used tomanufacture a flip-chip mounted semiconductor device, and the flip-chipmounted semiconductor device is manufactured in a form in which the film2 for semiconductor back surface of the dicing tape-integrated film 1for semiconductor back surface is pasted to the back surface of thesemiconductor chip. Therefore, the dicing tape-integrated film 1 forsemiconductor back surface of the present invention can be used for aflip-chip mounted semiconductor device (a semiconductor device in a formin which the semiconductor chip is fixed to an adherend such as asubstrate by a flip-chip bonding method).

As in the dicing tape-integrated film 1 for semiconductor back surface,the film 2 for semiconductor back surface can be used for a flipchip-mounted semiconductor device (a semiconductor device in a state orform where the semiconductor chip is fixed to an adherend such as asubstrate by a flip chip bonding method).

(Semiconductor Wafer)

The semiconductor wafer is not especially limited as long as it is aknown or common semiconductor wafer, and semiconductor wafers made ofvarious materials can be appropriately selected and used. In the presentinvention, a silicon wafer can be suitably used as the semiconductorwafer.

(Method for Producing Semiconductor Device)

Hereinafter, the method for producing a semiconductor device accordingto the present embodiment will be described with reference to FIGS. 2Ato 2D. FIGS. 2A to 2D are schematic cross-sectional views each showingone step of a method for producing a semiconductor device when thedicing tape-integrated film 1 for semiconductor back surface is used.

In the semiconductor device producing method, the dicing tape-integratedfilm 1 for semiconductor back surface can be used to produce asemiconductor device. Specifically, the producing method includes atleast a step of bonding a semiconductor wafer onto the film forsemiconductor back surface in the dicing tape-integrated film forsemiconductor back surface, a step of dicing the semiconductor waferwith a cutting depth so controlled as to fall within a rangeoverstepping one surface of the pressure-sensitive adhesive layer thatfaces the film for semiconductor back surface and not reaching anothersurface thereof that faces the base material to form a semiconductorchip, a peeling step of peeling the semiconductor chip from thepressure-sensitive adhesive layer of the dicing tape together with thefilm for semiconductor back surface, and a step of flip chip-connectingthe semiconductor chip onto an adherend.

[Mounting Step]

As shown in FIG. 2A, the separator that is appropriately provided on thefilm 2 for semiconductor back surface of the dicing-tape integrated film1 for semiconductor back surface is appropriately peeled off, asemiconductor wafer 4 is pasted to the film 2 for semiconductor backsurface, and the laminate is fixed by adhering and holding (mountingstep). At this time, the film 2 for semiconductor back surface isuncured (including a condition of being partially cured). Thedicing-tape integrated film 1 for semiconductor back surface is pastedto the back surface of the semiconductor wafer 4. The back surface ofthe semiconductor wafer 4 means the surface opposite to the circuitsurface (also referred to as a non-circuit surface or a non-electrodeforming surface). The pasting method is not especially limited, and apasting method by pressure-bonding is preferable. The pressure-bondingis performed by pressing by a pressing means such as a press roll.

[Dicing Step]

As shown in FIG. 2B, dicing of the semiconductor wafer 4 is performed.With this operation, the semiconductor wafer 4 is cut into individualpieces (cut into small pieces) having a prescribed size, and asemiconductor chip 5 is manufactured. The dicing is performed from thecircuit surface side of the semiconductor wafer 4 by a normal method,for example. For example, a cutting method called full cut in whichcutting is performed up to the dicing-tape integrated film 1 forsemiconductor back surface can be adopted in this step. The dicingapparatus used in this step is not especially limited, and aconventionally known apparatus can be used. Because the semiconductorwafer 4 is adhered and fixed with excellent adhesion by the dicing-tapeintegrated film 1 for semiconductor back surface having the film forsemiconductor back surface, chip cracks and chip fly can be suppressedand damages to the semiconductor wafer 4 can also be suppressed. Whenthe film 2 for semiconductor back surface is made from a resincomposition containing an epoxy resin, the generation of adhesiveprotrusion from the adhesive layer of the film for semiconductor backsurface can be suppressed or prevented on the cut surface even when thefilm 2 is cut by dicing. As a result, re-attachment (blocking) of thecut surfaces can be suppressed or prevented, and thus the picking-up tobe described below can be further successfully performed.

When expanding the dicing-tape integrated film 1 for semiconductor backsurface, a conventionally known expanding apparatus can be used. Theexpanding apparatus has a donut-shaped outer ring that can push down thedicing-tape integrated film 1 for semiconductor back surface through adicing ring and an inner ring that has a smaller diameter than the outerring and that supports the dicing tape-integrated film for semiconductorback surface. With this expanding step, generation of damages caused bythe contact between adjacent semiconductor chips can be prevented in thepickup step described later.

[Pickup Step]

The semiconductor chip 5 is peeled from the dicing tape 3 together withthe film 2 for semiconductor back surface by performing pickup of thesemiconductor chip 5 as shown in FIG. 2C to collect the semiconductorchip 5 that is adhered and fixed to the dicing-tape integrated film 1for semiconductor back surface. The pickup method is not especiallylimited, and various conventionally known methods can be adopted. Anexample of the method is a method of pushing up an individualsemiconductor chip 5 from the side of the base material 31 of thedicing-tape integrated film 1 for semiconductor back surface with aneedle and picking up the pushed semiconductor chip 5 with a pickupapparatus. The back surface of the semiconductor chip 5 that is pickedup is protected by the film 2 for semiconductor back surface.

[Flip-Chip Connecting Step]

As shown in FIG. 2D, the semiconductor chip 5 that is picked up is fixedto an adherend such as a substrate by a flip-chip bonding method(flip-chip mounting method). Specifically, the semiconductor chip 5 isfixed to an adherend 6 by a normal method in a form that the circuitsurface (also referred to as the surface, a circuit pattern formingsurface, or an electrode forming surface) of the semiconductor chip 5faces the adherend 6. The semiconductor chip 5 can be fixed to theadherend 6 while securing electrical conduction of the semiconductorchip 5 with the adherend 6 by contacting and pressing a bump 51 formedon the circuit surface side of the semiconductor chip 5 to a conductivematerial 61 such as solder for bonding that is adhered to a connectionpad of the adherend 6 and melting the conductive material (a flip-chipbonding step). At this time, a space is formed between the semiconductorchip 5 and the adherend 6, and the distance of the space is generallyabout 30 to 300 μm. After flip-chip bonding (flip-chip connection) ofthe semiconductor chip 5 onto the adherend 6, it is important to washthe facing surface and the space between the semiconductor chip 5 to theadherend 6 and to seal the space by filling the space with a sealingmaterial such as a sealing resin.

Various substrates such as a lead frame and a circuit board (a wiringcircuit board, for example) can be used as the adherend 6. The materialof the substrate is not especially limited, and examples thereof includea ceramic substrate and a plastic substrate. Examples of the plasticsubstrate include an epoxy substrate, a bismaleimide triazine substrate,and a polyimide substrate.

The material of the bump and the conductive material in the flip-chipbonding step are not especially limited, and examples thereof includesolders (alloys) of a tin-lead metal material, a tin-silver metalmaterial, a tin-silver-copper metal material, a tin-zinc metal material,and a tin-zinc-bismuth metal material, a gold metal material, and acopper metal material.

In the flip-chip bonding step, the bump of the circuit surface side ofthe semiconductor chip 5 and the conductive material on the surface ofthe adherend 6 are connected by melting the conductive material. Thetemperature when the conductive material is molten is normally about260° C. (250 to 300° C., for example). The dicing tape-integrated filmfor semiconductor back surface of the present invention can have heatresistance so that it can resist a high temperature in the flip-chipbonding step by forming the film for semiconductor back surface with anepoxy resin, or the like.

In this step, the facing surface (an electrode forming surface) and thespace between the semiconductor chip 5 and the adherend 6 are preferablywashed. The washing liquid that is used in washing is not especiallylimited, and examples thereof include an organic washing liquid and awater washing liquid. The film for semiconductor back surface in thedicing tape-integrated film for semiconductor back surface of thepresent invention has solvent resistance to the washing liquid, and doesnot substantially have solubility in these washing liquids. Because ofthat, various washing liquids can be used as the washing liquid, andwashing can be performed by a conventional method without requiring aspecial washing liquid.

Next, a sealing step is performed to seal the space between theflip-chip bonded semiconductor chip 5 and the adherend 6. The sealingstep is performed using a sealing resin. The sealing condition is notespecially limited. Thermal curing of the sealing resin is performednormally by heating the sealing resin at 175° C. for 60 to 90 seconds.However, the present invention is not limited to this, and curing can beperformed at 165 to 185° C. for a few minutes, for example. By thethermal treatment in this step, not only the sealing resin but also thefilm 2 for semiconductor back surface is thermally cured. Accordingly,both the sealing resin and the film 2 for semiconductor back surface arecured and shrunk along with the progress of the thermal curing. As aresult, the stress to be given to the semiconductor chip 5 owing to thecuring shrinkage of the sealing resin can be cancelled or relaxedthrough the curing shrinkage of the film 2 for semiconductor backsurface. In this step, the film 2 for semiconductor back surface can becompletely or almost completely thermally cured, and can be bonded ontothe back surface of the semiconductor element with excellent tackiness.Further, the uncured film 2 for semiconductor back surface according tothe invention can be thermally cured together with the sealing materialin the sealing step, so that it is not necessary to newly add a step ofthermal curing the film 2 for semiconductor back surface.

The sealing resin is not especially limited as long as it is a resinhaving insulation properties, and can be appropriately selected fromsealing materials such as a known sealing resin. However, an insulatingresin having elasticity is preferable. Examples of the sealing resininclude a resin composition containing an epoxy resin. Examples of theepoxy resin include epoxy resins described above. The sealing resin witha resin composition containing an epoxy resin may contain athermosetting resin such as a phenol resin other than the epoxy resin, athermoplastic resin, and the like as a resin component besides the epoxyresin. The phenol resin can also be used as a curing agent for the epoxyresin, and examples of the phenol resin include the above-describedphenol resins.

In the semiconductor device (flip chip-mounted semiconductor device)produced using the dicing tape-integrated film 1 for semiconductor backsurface or the film 2 for semiconductor back surface, the film forsemiconductor back surface is bonded onto the back surface of thesemiconductor chip. Therefore, various types of marking can be appliedwith excellent visibility. In particular, even when the marking methodis a laser marking method, laser marking can be applied with anexcellent contrast ratio, and it is possible to observe various kinds ofinformation (for example, literal information and graphical information)applied by laser marking with good visibility. At the laser marking, aknown laser marking apparatus can be utilized. As the laser, it ispossible to utilize various lasers such as a gas laser, a solid-statelaser, and a liquid laser. Specifically, as the gas laser, any known gaslasers can be utilized without particular limitation, but a carbondioxide laser (CO₂ laser) and an excimer laser (ArF laser, KrF laser,XeCl laser, XeF laser, or the like) are suitable. As the solid-statelaser, any known solid-state lasers can be utilized without particularlimitation, but a YAG laser (such as Nd:YAG laser) and a YVO₄ laser aresuitable.

Because the semiconductor device that is manufactured using the dicingtape-integrated film for semiconductor back surface or the film forsemiconductor back surface of the present invention is a semiconductordevice that is mounted by a flip-chip mounting method, the semiconductordevice has a shape thinner and smaller than a semiconductor device thatis mounted by a die bonding mounting method. Because of this, thesemiconductor device can be suitably used as various electronicapparatuses and electronic parts or materials and members thereof.Specific examples of the electronic apparatus in which the flip-chipmounted semiconductor device of the present invention can be usedinclude a portable phone, PHS, a small computer such as PDA (personaldigital assistant), a notebook personal computer, Netbook (trademark),or a wearable computer, a small electronic apparatus in which a portablephone and a computer are integrated, Digital Camera (trademark), adigital video camera, a small television, a small game machine, a smalldigital audio player, an electronic organizer, an electronic dictionary,an electronic apparatus terminal for an electronic book, and a mobileelectronic apparatus (portable electronic apparatus) such as a smalldigital type clock or watch. Examples of the electronic apparatus alsoinclude an electronic apparatus other than a mobile type apparatus(i.e., a stationary apparatus) such as a desktop personal computer, aflat-panel television, an electronic apparatus for recording and playingsuch as a hard disc recorder or a DVD player, a projector, or amicromachine. Examples of the electronic parts or materials and membersof the electronic apparatus and electronic parts include a component ofCPU and components of various recording apparatuses such as a memory anda hard disk.

EXAMPLES

Hereinafter, the present invention will be described in detail withreference to examples. However, the invention is not limited to thefollowing examples unless it exceeds the gist thereof. “Part(s)” in eachexample is on a weight basis unless otherwise stated.

Example 1

In methyl ethyl ketone, 53 parts of an epoxy resin (trade name “HP-4700”manufactured by DIC Corporation), 69 parts of a phenolic resin (tradename “MEH-7851H” manufactured by Meiwa Plastic Industries, Ltd.), 153parts of spherical silica (trade name “SE-2050-MCV” manufactured byAdmatechs Co., Ltd.), and 7 parts of a coloring agent (trade name“ORIPAS B-35” manufactured by Orient Chemical Industries Co., Ltd.),based on 100 parts of an acrylate-based polymer (trade name “TeisanResin SG-P3” manufactured by Nagase ChemteX Corporation) containingethyl acrylate and methyl methacrylate as main components, weredissolved, to prepare a solution of an adhesive composition having asolid concentration of 22% by weight.

The solution of the adhesive composition was applied onto arelease-treated film, as a release liner (separator), made of apolyethylene terephthalate film having a thickness of 50 μm, which hadbeen subjected to a silicone release treatment, and then dried at 130°C. for 2 minutes to produce a film for semiconductor back surface havinga thickness of 25 μm.

Example 2

In methyl ethyl ketone, 9 parts of an epoxy resin (trade name “HP-4700”manufactured by DIC Corporation), 12 parts of a phenolic resin (tradename “MEH-7851H” manufactured by Meiwa Plastic Industries, Ltd.), 69parts of spherical silica (trade name “SE-2050-MCV” manufactured byAdmatechs Co., Ltd.), and 7 parts of a coloring agent (trade name“ORIPAS B-35” manufactured by Orient Chemical Industries Co., Ltd.),based on 100 parts of an acrylate-based polymer (trade name “TeisanResin SG-P3” manufactured by Nagase ChemteX Corporation) containingethyl acrylate and methyl methacrylate as main components, weredissolved, to prepare a solution of an adhesive composition having asolid concentration of 22% by weight.

The solution of the adhesive composition was applied onto arelease-treated film, as a release liner (separator), made of apolyethylene terephthalate film having a thickness of 50 μm, which hadbeen subjected to a silicone release treatment, and then dried at 130°C. for 2 minutes to produce a film for semiconductor back surface havinga thickness of 25 μm.

Example 3

In methyl ethyl ketone, 153 parts of spherical silica (trade name“SE-2050-MCV” manufactured by Admatechs Co., Ltd.) and 7 parts of acoloring agent (trade name “ORIPAS B-35” manufactured by Orient ChemicalIndustries Co., Ltd.), based on 100 parts of an acrylate-based polymer(trade name “Teisan Resin SG-P3” manufactured by Nagase ChemteXCorporation) containing ethyl acrylate and methyl methacrylate as maincomponents, were dissolved, to prepare a solution of an adhesivecomposition having a solid concentration of 22% by weight.

The solution of the adhesive composition was applied onto arelease-treated film, as a release liner (separator), made of apolyethylene terephthalate film having a thickness of 50 μm, which hadbeen subjected to a silicone release treatment, and then dried at 130°C. for 2 minutes to produce a film for semiconductor back surface havinga thickness of 25 μm.

Comparative Example 1

In methyl ethyl ketone, 7 parts of a coloring agent (trade name “ORIPASB-35” manufactured by Orient Chemical Industries Co., Ltd.), based on100 parts of an acrylate-based polymer (trade name “Teisan Resin SG-P3”manufactured by Nagase ChemteX Corporation) containing ethyl acrylateand methyl methacrylate as main components, was dissolved, to prepare asolution of an adhesive composition having a solid concentration of 22%by weight.

The solution of the adhesive composition was applied onto arelease-treated film, as a release liner (separator), made of apolyethylene terephthalate film having a thickness of 50 μm, which hadbeen subjected to a silicone release treatment, and then dried at 130°C. for 2 minutes to produce a film for semiconductor back surface havinga thickness of 25 μm.

Comparative Example 2

In methyl ethyl ketone, 109 parts of an epoxy resin (trade name“HP-4700” manufactured by DIC Corporation), 141 parts of a phenolicresin (trade name “MEH-7851H” manufactured by Meiwa Plastic Industries,Ltd.), 120 parts of spherical silica (trade name “SE-2050-MCV”manufactured by Admatechs Co., Ltd.), and 7 parts of a coloring agent(trade name “ORIPAS B-35” manufactured by Orient Chemical IndustriesCo., Ltd.), based on 100 parts of an acrylate-based polymer (trade name“Teisan Resin SG-P3” manufactured by Nagase ChemteX Corporation)containing ethyl acrylate and methyl methacrylate as main components,were dissolved, to prepare a solution of an adhesive composition havinga solid concentration of 22% by weight.

The solution of the adhesive composition was applied onto arelease-treated film, as a release liner (separator), made of apolyethylene terephthalate film having a thickness of 50 μm, which hadbeen subjected to a silicone release treatment, and then dried at 130°C. for 2 minutes to produce a film for semiconductor back surface havinga thickness of 25 μm.

(Evaluation)

The films for semiconductor back surface produced in Examples 1 to 3 andComparative Examples 1 and 2 were evaluated as follows. The results areshown in Table 1.

<Measurement of Adhering Strength of Film for Semiconductor Back Surfaceto Semiconductor Wafer>

The adhering strength (N/10 mm width) of the film for semiconductor backsurface to a semiconductor wafer was measured as follows: A siliconwafer as a semiconductor wafer was put on a hot plate, and at apredetermined temperature (50° C.), a film for semiconductor backsurface having a length of 150 mm and a width of 10 mm, of which theback surface had been reinforced with a pressure-sensitive adhesive tape(trade name “BT-315”, manufactured by Nitto Denko Co., Ltd.), was bondedto the silicon wafer by pressing the film with a 2-kg roller moved onceback and forth thereon. Subsequently, this was kept on the hotplate (50°C.) for 2 minutes, and then kept at room temperature (23° C. or so) for20 minutes. After that, using a peeling tester (trade name “AutographAGS-J” manufactured by SHIMADZU CORPORATION), the back-reinforced filmfor semiconductor back surface was peeled at a temperature of 70° C., apeeling angle of 180 degrees and a tension rate of 300 mm/min (that is,the film for semiconductor back surface was peeled from thesemiconductor wafer at the interface between the two), and the maximumpeeling load (the maximum load except the initial peak top) wasmeasured. The maximum load was taken as the adhering strength of thefilm for semiconductor back surface to the semiconductor wafer.

<Measurement of Rupture Elongation>

Using a roll laminator (device name “MRK-600” manufactured by MCK CO.,LTD.), a film for semiconductor back surface produced at 70° C. and 0.2MPa was laminated to obtain a 100 μm-thick film for semiconductor backsurface for measurement. The film for semiconductor back surface formeasurement was cut to a size of 10 mm (width)×30 mm (length) to obtaina test piece. A tension test was then conducted at a tension rate of 50mm/min, a chuck-to-chuck distance of 10 mm, and a temperature of 25° C.using “AUTOGRAPH ASG-50D Model” (manufactured by Shimadzu Corporation)as a tension tester. A rupture elongation (%) was determined based onthe following formula:a rupture elongation (%)={(D₁-D₀)/D₀}×100%

where D₀ is a chuck-to-chuck distance before the test, and D₁ is achuck-to-chuck distance when the test piece was ruptured.

<Method for Measuring Degree of Swelling>

About 0.1 g of a sample was sampled from the film for semiconductor backsurface and precisely weighed (weight of sample) and, after the samplewas wrapped in a mesh sheet, it was immersed in about 50 mL of ethanolat room temperature for 1 week. Thereafter, a solvent-insoluble matter(content in the mesh sheet) was taken out of ethanol and air-dried atroom temperature until the weight change reached 1% or less. Thesolvent-insoluble matter after air drying was weighed (weight W1 afterimmersing and air drying). Then, the solvent-insoluble matter was driedby heating at 130° C. for about 2 hours, and the solvent-insolublematter after drying was weighed (weight W2 after immersing and drying byheating). A degree of swelling (% by weight) was calculated according tothe following expression (a).Degree of swelling (% by weight)=[(W1−W2)/W2]×100  (a)<Method for Evaluating Peeling Property (Reworkability)>

A semiconductor wafer (diameter: 8 inches, thickness: 0.6 mm; a siliconmirror wafer) was subjected to a back surface polishing treatment and amirror wafer having a thickness of 0.2 mm was used as a workpiece. Themirror wafer (workpiece) was bonded onto the film for semiconductor backsurface by roller press-bonding at 70° C. After heat release to roomtemperature, the film for semiconductor back surface was peeled from anend thereof by the pressure-sensitive adhesive tape BT-315 (manufacturedby Nitto Denko Co., Ltd.). The case where the film for semiconductorback surface was peeled without rupture and without generating anyresidue on the wafer, or the generated residue was cleanly removed byethanol was evaluated as “◯”. The case where the film for semiconductorback surface was ruptured, and the case where the residue was generatedon the wafer was evaluated as “x”.

TABLE 1 Exam- Exam- Exam- Comparative Comparative ple 1 ple 2 ple 3Example 1 Example 2 Rupture 2 500 700 1000 100 elongation at 25° C. [%]Adhering 1 5 7 7 8 strength at 70° C. Degree of 1 2 1 0.5 0.5 swelling[% by weight] Peeling ∘ ∘ ∘ x x property (reworkability)

From Table 1, the films for semiconductor back surface according toExamples 1 to 3 had a good peeling property (reworkability). On theother hand, the films for semiconductor back surface according toComparative Examples 1 and 2 had too high a rupture elongation or toohigh an adhering strength, which caused a poor peeling property.

What is claimed is:
 1. A film for semiconductor back surface having: anadhering strength at 70° C. of 7 N/10 mm or less to a wafer before thefilm is thermally cured; and a rupture elongation at 25° C. of 700% orless, wherein the film contains an acrylic resin and 50 to 200 parts byweight of an inorganic filler based on 100 parts by weight of theacrylic resin.
 2. The film for semiconductor back surface according toclaim 1, wherein the film has a degree of swelling due to ethanol of 1%by weight or more.
 3. A dicing tape-integrated film for semiconductorback surface, comprising: a dicing tape comprising a base material and apressure-sensitive adhesive layer that are laminated in this order; andthe film for semiconductor back surface according to claim 1 laminatedon the pressure-sensitive adhesive layer of the dicing tape.
 4. A methodfor producing a semiconductor device using the dicing tape-integratedfilm for semiconductor back surface according to claim 3, the methodcomprising: bonding a semiconductor wafer onto the film forsemiconductor back surface of the dicing tape-integrated film forsemiconductor back surface; dicing the semiconductor with a cuttingdepth so controlled as to fall within a range overstepping one surfaceof the pressure-sensitive adhesive layer that faces the film forsemiconductor back surface and not reaching another surface of thepressure-sensitive adhesive layer that faces the base material to form asemiconductor chip; peeling the semiconductor chip from thepressure-sensitive adhesive layer of the dicing tape together with thefilm for semiconductor back surface; and flip chip-connecting thesemiconductor chip onto an adherend.